Friday, April 24, 2009

It's the best time of the year! Stanley Cup Playoffs are here! In an earlier comment, I predicted the teams for the Conference Finals: Detroit and Chicago in the West; Boston and Carolina in the East (from which one can infer - correctly I might add - that I predicted the Rangers would beat the Caps!)

All comments regarding the playoffs and other hockey news is welcome here!

"Is there something we don’t know about GRAVITY?”* was the cover story for the March 2009 issue of Astronomy. This piqued my interest since I recall reading an article last year about the Pioneer spacecraft not being where they were expected to be (of course, I neglected to bookmark it and now can’t find it. Help, anyone?), and I was curious if this article expanded on the Pioneer anomaly.

The author, Dr. John D. Anderson (formerly of NASA’s JPL and now a consultant for the Juno and Rosetta space missions), began with a very brief historical overview of gravitational theories, from Newton to Einstein. To date, Newtonian and Einsteinian (sp?) gravity has worked quite well for astronomers. However, there have been some curious anomalies.

The first two anomalies mentioned are relatively minor. First, the Moon’s orbit around the Earth is becoming more elliptical.

“[James G.] Williams [of Caltech’s JPL] reported in 2006 that the distance difference between the Moon’s farthest and closest approach to Earth is increasing nexpectedly by about 0.2 inches (6 millimetres) per year. ...

“After accounting for changes expected from tidal friction, Williams still has a residual change in the Moon’s orbit that he can’t explain.”

Second, the value of the Astronomical Unit (AU) is increasing by about 7 metres (or 0.000 000 047%) per century. IMO, these two anomalies can be considered trivial since the changes are so extremely small that one could consider them, and their effects, negligible.

Dr. Anderson then focused on the Pioneer Anomaly, that there seems to be some mysterious and unexpected force slowing down the probes:

“The tracking data showed that, in 1998, the Pioneer 10 spacecraft was about 36,000 miles (58,000 kilometres) short of what we expected, based on the laws of motion given by Newton and Einstein.. …

“The situation with Pioneer 11 is similar. …we have determined the spacecraft is about 3,700 miles (6,000 km) short of its predicted distance. It is as if something is putting the brakes on both spacecraft by just the right amount that they both change their speed at the same amount in the same interval of time.”

The final anomaly mentioned deals with “anomalous orbital energy changes of six spacecraft that flew by Earth for gravity assists… These changes do not obey Newton’s law of gravity.” These spacecraft include Galileo, Rosetta, and NEAR Shoemaker. The unexpected speed increases were small (from 1.8 mm/s for Rosetta to 13.5 mm/s for NEAR). At first glance, the data appears to suggest an inverse proportional relationship between magnitude of speed increase and closest approach to Earth (the closer the approach to Earth, the greater the magnitude of speed increase).

Are there explanations for these anomalies using already understood physical mechanisms? A proposal to explain the Pioneer anomaly is heat radiating from the Pioneer spacecraft. However, Dr. Anderson notes that if this were the case, then the rate of deceleration would have decreased instead of staying constant as observed for 11 years. With respect to the fly-by anomaly, currently understood effects have been found to be negligible or only account for a small fraction of the speed increase.

So is a new theory of gravity required? Dr. Anderson focused on one proposal - modified Newtonian dynamics, or MOND. Anderson notes that MOND “is not a theory, but a modification that simply fits the data.” The modifications are due to another anomaly, this one at the galactic scale.

“Since the 1970s, astronomers have known that the outer regions of galaxies appear to violate Newton’s gravity laws. We would expect the stars in a galaxy’s outer regions to travel in elliptical orbits with their orbital speeds decreasing with increasing distance. However, this is not observed. Instead of decreasing, the speeds are essentially constant over a wide region of the galaxy.”

The current theory in play to explain the above effect is “that the galaxies actually contain large quantities of unseen material [dark matter] that hold the stars in the galaxy.” Anderson acknowledged that if MOND is correct, dark matter would be superfluous and discarded.

I found Dr. Anderson’s article interesting and informative. First, I find astronomy very interesting (personal interest). Second, the article never made over-reaching and/or grandiose claims. Dr. Anderson simply stated the facts and the direction of research being done, but reported them in a manner that grasped my attention and interest. Finally, the article served as another reminder that we don’t know everything about our world and universe. Current theories, as well as they may perform, represent an incomplete view of our world and universe. Alternative thinking should not only be scrutinized, but welcomed.

Monday, March 23, 2009

I find that free time to spend at EE is hard to find these days. One of my goals is to "tie up some loose ends" here that have been bugging me.

One of them is an apology to comments of Full Disclosure. One of these days, I will learn to shut down comments on specific threads.

I am also introducing two more blogs to the blogroll. I find Allen MacNeill to be one of the more engaging critics over at TT. Thus, I am re-including "The Evolution List" to the Blog Roll.

The second one is for the "truly brave" to dare to lurk/comment (for the dense, I'm joking). After lurking around "The Swamp"/"After the Bar Closes", I don't see what the big deal is about foul-mouthed adult men and women. After all, I've been to Fort McMurray! ;) So in a continuing effort to provide balance to EE, I'm including AtBC in the Blog Roll.

To close, I'm still alive. I'm thankful to be working and I am busy at home with family and home projects. But I also hope to still contribute to EE every now and then.

UPDATE (5-Apr-2009): AtBC, being a forum not a blog, is being moved to the FYI section.

Wednesday, March 11, 2009

This was the second time I was asked/accused of being a creationist at TT. I don't like this question for several reasons:

1. It assumes there is something wrong with being a creationist (there isn't),2. It's dishonest,2a. The question seems more suited to distracting from the original argument,2b. It isn't a strict yes or no question3. If the one question answers yes, then, in the questioner's mind, this poisons all arguments from the one questioned.

To clear the air, I've offered to give full disclosure, but this has the drawback of never completely satisfying the questioner. I could make my position clear, but there would either be some aspect I'd be "overlooking" or it would give the questioner reason to disregard my arguments.

That said, I offer the following as insight as to where I am coming from. I will not respond to any comments on this thread. In fact, as soon as I see them, I will delete them.

-I am a Christian who accepts the Nicene Creed and the doctrine of the Trinity (God the Father, Son, and Holy Spirit)-I believe God worked through 40 different people to create the 66 documents that make up the canonical Bible and I believe that the overarching message to be consistent and (in general) non-conflicting-I believe Jesus entered human history and died on the cross to bridge the gap between God and man that was created by man's disobedience to God.-I believe the universe is approximately 14 billion years old-I believe the Earth is approximately 4.6 billion years old-As a structural engineer, I depend on the laws of physics and chemistry in order to do my work properly, and I have no problem believing the validity of such laws.-As a means to acquiring knowledge, I believe science and its laws have finite and definable limits, and it is the duty of science to determine such limits.

It's late, but I wanted to draw attention to (IMHO) is one of the more neutral and balanced essays regarding the scientific status of Intelligent Design. I hope to write in more detail about it at a later date.

Saturday, February 7, 2009

I can be fairly patient as an Oiler fan, but I've reached my limit. Nine years of mediocrity is enough! The Oilers need to clean house and fire head coach, Craig MacTavish! And while they are at it, clean house and let the rest of the coaching staff go, too.